Interfacial regulation of aqueous synthesized metal-semiconductor hetero-nanocrystals

Abstract

Integrating metal and semiconductor components to form metal-semiconductor heterostructures is an attractive strategy to develop nanomaterials for optoelectronic applications, and the rational regulation of their heterointerfaces could effectively influence their charge transfer properties and further determine their performance. Considering the natural large lattice mismatch between metal and semiconductor components, defects and low crystalline heterointerfaces could be easily generated especially for heterostructures with large contacting areas such as core-shell and over quantum-sized nanostructures. The defective interfaces of heterostructures could lead to the undesirable recombination of photo-induced electrons and holes, which would decrease their performances. Based on these issues, the perspective focusing on the most recent progress in the aqueous synthesis of metal-semiconductor heterostructures with emphasis on heterointerface regulation is proposed, especially in the aspect of non-epitaxial growth strategies initiated by cation exchange reaction (CER). The enhanced optoelectronic performance enabled by precise interfacial regulations is also illustrated. We hope this perspective could provide meaningful insights for researchers on nano synthesis and optoelectronic applications.

Aqueous Topological Synthesis of Au@semiconductor Core–Shell Nanocrystals with Morphology and Composition Engineering

“…According to the theory of hard and soft acids and bases, TPP is a soft base that has different coordination abilities with metal ions. In this reaction, metal nitrate aqueous solution and TPP, which was dissolved by a trace amount of toluene, were introduced into Au@Ag 2 X NCs aqueous colloid and stirred for a while to form a uniform mixture with a solid-solution-liquid interface (TPP-aqueous-toluene), and then through hydrothermal treatment, the TPP would coordinate with soft acid Ag + in the amorphous Ag 2 X shell preferentially, which induced the CER between the metal cation in solution and Ag + in the shell, forming a single-crystalline semiconductor shell with low defect heterointerfaces, ,, successfully achieving topological conversion of aqueous cations and obtaining NMS C–S NCs with various compositions. The core–shell structure was not changed or be damaged significantly after CER, which was due to the topotactic nature of CER transformation.…”